Ignition device



June 12, 1934. E. B. NOWOSIELSKI IGNITION DEVICE Filed Aug. 9, 1930 9 Tu FII INVENTOR Edward fl. jl/ozoasz'elsli 12 /3 ATTORNEY Patented June12, 1934 UNITED STATES PATENT OFFICE IGNITION DEVICE Edward B.Nowosielski, Bloomfield, N. J., signer to Eclipse Aviation Corporation,

as- East The present invention relates to ignition devices for internalcombustion engines, and more particularly to novel means for shieldingspark plugs.

I One of the objects of the invention is to provide novel means as apart of the structure of a spark plug for efficiently shielding all ofthe electrical parts of said plug to prevent interference with theoperation of other sensitive electrical apparatus, such as radioequipment, for example.

Another object is to provide a novel and quickly detachable connectorand shield for a spark plug whereby said shield constitutes a part ofthe structure of the plug.

Another object is to provide a novel improved form of spark plugembodying a shield therefor whereby said shield constitutes a part ofthe plug structure to maintain the various other'parts of the spark plugin assembled relation and to provide for quick assembly and disassemblyof the plug for purposes of inspection and replacement df said parts.

A further object is to provide an ignition device of novel constructionembodying a spark plug and shielding means for said plug whichcbnstitutes a part of the structure thereof, whereby said shieldingmeans may be adjusted to anyangle or position about the axis of saidplug, as desired.

A still further object is to provide an improved spark plug structureincluding a shield, whereby the number of individual parts is reduced toa minimum, thus reducing the cost of manufacture and simplifyingassembly, and which is both mechanically and electrically strong and iscapable of long service under severe conditions of usage as, forexample, in aircraft engines.

Other objects and advantages of the invention will appear more fullyhereinafter fromconsideration of the detailed description which follows.

Although only one embodiment of the invention is described andillustrated in the accompanying drawing, it is to be expresslyunderstood that this drawing is for the purpose of illustration only,and is not to be construed as a definition of the limits of theinvention, reference being had for this purpose to the appended claims.

In the drawing:

Fig. 1 is an end view of one embodiment of the present invention;

Fig. 2 is a sectional side view taken on line 2--2 of Fig. 1; and

Fig. 3 is a drawn-out side view of the embodi-' ment of Fig. 1 showing"the separate parts thereof and indicating the manner of cooperationtherebetween when assembled.

Referring now to the drawing, wherein like reference characters refer tolike parts throughout the several views, and particularly to Fig. 2, thedevice comprises a body portion 4 which is threaded at 5 for engagementwith an engine cylinder (not shown) and provided with the usual flange 6which is adapted to contact with a gasket (not shown) inserted betweenthe flange and the engine cylinder in order to make the joint gas-tight.The body portion is counterbored at 7, and the negative electrode 8,which is carried by the body portion in any suitable manner, extendsinto said bore tosubstantially 30 the center thereof for cooperationwith the sparking end 9 of the positive electrode 10. The latter isembedded in an insulator member 11 of some suitable insulating materialsuch as porcelain, and which, in the form shown, is provided 75 with acentral cylindrical portion 12, a frustoconical portion 13 surroundingthe sparking end of the electrode 10, and with a frusto-conical recess14 surrounding said electrode adjacent it's I other end. The insulatormember 11 is held in position in the body portion by means of a sleeve15 which is threaded at 16 for engagement with .,..said body portion andprovided with an inwardly projecting lip or flange 17 which engages theshoulder 18 of said insulator. The sleeve 15 is knurled at its lower endas indicated at 150. to facilitate assembly thereof with the body 4, andis provided with circumferentially spaced apertures 17a to permitcirculation of air around the insulator 11 to cool the latter. Ametallic bushing 19, preferably of copper or other suitable malleablematerial, is inserted between the shoulder 18 and the lip 1'7 to preventbreaking of the insulator when the sleeve member 15 is screwed tightlyon the body portion 4. A similar bushing 20 is inserted between thelower end of the cylindrical portion 12 of the insulator and the bodyportion 4 for the same purpose, and also to form a gas-tight seal. Theelectrode 10 is adapted to cooperate with an extension 10a which isprovided with a tapered portion 21terminating in a sharp point forpiercing an insulated ignition cable, as will be apparent hereinafter,and is also provided with a pin 10b for insertion in a bore in saidelectrode 10. The tapered portiorf'21 maybe threaded, if desired, tohold the extension 10a more firmly in the cable. Due to the separabilityof parts 10 and 10a it is unnecessary to separate the extension 10a fromthe cable each time the plug is disassem'oled and the cable does nothave to be pierced each time the plug is assembled after the firstassembly.

A metallic casing 22 is provided of some suitable shielding material,such as aluminum, and coacts with sleeve to constitute a shield for thespark plug. Said shield is in the form of a cylinder having a boss 23projecting at right angles thereto, said boss being provided with a i 2from.

bore 24 for the reception of an ignition cable 25. The shield is alsoprovided with a yielding lower portion having a plurality ofcircumferentially spaced longitudinal slits 26 extending upward from thelower end of the shield for substantially half its length. This yieldingportion formed by slits 26 cooperates with other parts of the plug toprovide means of rapid and easy assembly and disassembly of the sparkplug tructure. Said shield is so formed, as by stampthat it may beassembled with a sliding 'ictional fit with the sleeve 1c, slits 28allowa slight resilient expansion of the lower porof the cylindricalcasing so as to receive lock these parts together in a readily breakablefrictional connection. The frictional telescoping engagementbetweencylinder 22 and sleeve 15 also permits angular adjustment of thecylinder about the longitudinal axis of the plug so as to avoid tienecessity of any sharp bends in the ignition cable, which are conduciveto insulation failures.

The remaining element of the spark plug structure consists of a highpotential insulating member 29 formed of any suitable material, such asporcelain, which is disposed within the metallic casing 22 but entirelydisconnected there- The shape of the outer surface of the insulatingmember 29 corresponds in general to that of the interior oi" themetallic housing and is provided with a vertical bore 30 of suflicientdiameter to provide adequate clearance for the electrode extension 10aand with a horizontal or transverse bore 31 extending through saidmemher and intersecting the vertical bore 38 for the reception of thecable 25; If desired, said insulating member 29 may be split into twoparts along the axis of bore 30, but it is preferable that this piece beformed as an integral member, as shown in Figs. 2 and 3. When theinsulated cable 25 is passed through the bore 24 of the casing 22 andinserted into the transverse bore 31 of the insulator member 29, it isadapted to be pierced by the sharp point 21 on the electrode extension10a so that the latter makes an electrical contact with the strandedwire 32 of the ignition cable. The insulator member 29 is also formedwith a frusto-conical portion 33 which is adapted to cooperate with thefrustoconical recess '14 in the insulator member 11 and is furtherprovided with an annular recess 34 surrounding the frusto-conicalportion 33 and adapted to receive the end portion 35 of the insulator11, thereby forming a baffle between the insulators 11 and 29 to preventmoisture and foreign material coming in contact with electrode 10 whensaid insulators are held in assembled relation by means of the casing 22and to prevent overheating of the insulator 29. A metallic washer 36 isinterposed between the insulator 29 and the sleeve 15.

The parts may be assembled as follows: The metallic washer 20 is placedinto the body portion 4 and the insulator member 11 is inserted thereinso that the end 9 of electrode 10 cooperates with the negative electrode8. The metallic washer l9 isthen placed over the shoulder 18 of theinsulator 11 and sleeve 15 is screwed onto the body portion to firmlyhold said insulator in position. The insulator 29 is placed into thecasing 22 in such position that the opening of the transverse bore 31 isadjacent the bore 24 of the boss 23, and the cable 25 is inserted intothe bore 31. The electrode extension 10a is then inserted into the bore30 and pushed or screwed into the cable 25 so as to pierce theinsulation of said cable thereby coming into electrical contact with thestranded wire 31. This latter assembly is placed over the insulator 11with washer 36 interposed therebetween and secured to sleeve 15 bytelescoping the lower portion of the casing 22 over said sleeve andforcing said casing downward until indentation 27 engages groove 28,thereby clamping the shield to the body of the plug, causing the pin 10bto enter the bore in electrode 10 to make an electrical connectionbetween the spark plug and the ignition. cable, and holding theinsulator 29 firmly in position with the insu- 1 0 later 11.

There is thus provided a novel spark plug structure including a shield,which may be easily and quickly assembled and disassembled and which isadapted for use with any type of intemal combustion engine, preferablyon aircraft, where high frequency discharges of the spark plug produceundesirable interference with other electrical equipment, such as radioreceivers, for example. The shield constitutes a part of the spark. plugstructure and is light in weight, relatively inexpensive to manufacture,and comprises a minimum of parts (namely two), each of which is easilyseparable from the other parts of the plug structure for inspection orreplacement. Adequate means are provided for thoroughly insulating thepositive electrode of the spark plug from the metallic parts of theshield, thus providing for electrical shielding without impairing thecharge-ignition function of the spark plug.

From actual use of this shield, it has been found that a cooler sparkplug is obtained, the large metallic surface offering greateropportunity ior dissipation and conduction of heat away from the hotterportions of the spark plug, and the apertures 17a aifording acirculation of air around the insulator ii. The novel spark plugdisclosed herein permits the ignition cable to enter the shield thereofand to be connected to the spark plug terminal in a horizontal plane andalso provides that the shield may be rotated about the longitudinal axisof the plug, circumferential slippage taking place between the metalliccasing 22 and the sleeve 15, thus enabling the cable to be adjusted toany angular position and to avoid the necessity for sharp bends therein,which are well-known to be conducive to insulation failures. The mannerof mechanically and electrically connecting the cable to the spark plugis extremely simple and efilcient.

It will be obvious that the invention is not limited to the formdescribed and illustrated in the drawing, but is capable of a variety ofmechanical embodiments. Various changes may be made in the form, detailsof construction, and arrangement of the parts, without departing fromthe spirit of the invention, and reference is therefore to be had to theappended claims for a deflnition oi the limits of the invention.

What is claimed is:

1. An ignition device comprising in combination, a spark plug structureincluding a member arranged for attachment to a cylinder of an engineand having an electrode therein; a cooperating electrode assembly fittedwithin said member and comprising an electrode surrounded by aninsulator having a cylindrical central portion, a frusto-conical portionadjacent to the sparking end of said second electrode, and a frus-'to-conical recess at the other end, said electrode having a removableextension one end of which is pointed for piercing a cable, a secondinsulator provided with a conical projection-adapted to fit within therecess of said first insulatorand having a longitudinal bore extendingtherethrough for receiving said extension and a transverse boreintersecting said first bore arranged for the reception of an insulatedignition cable, means for holding said first insulator within said bodyportion of the plug, shielding means for the plug adapted tofrictionally engage said last-mentioned means and to fit over saidsecond insulating member for holding the latter in assembled relationwith the first insulating member, said shielding means being adapted forrotation about the longitudinal axis of said plug and an insulatedignition cable extending into the transverse bore of said secondinsulating member through said shielding means and in electrical contactwith the electrode extension.

2. An ignition device comprising in combination, a spark plug structureincluding a shell arranged for attachmentto'a cylinder of an engine andhaving an electrode, a cooperating electrode assembly carried bysaidshell and including a second electrode adapted to form a spark gapwith said first electrode, a shield surrounding the upper portion ofsaid shell and means adapted for frictional engagement with said shieldand threaded engagement with said shell to complete the shielding ofsaid plug structure.

3. A spark plug structure comprising a member arranged for attachment toa cylinder of an engine and having an electrode therein, a cooperatingelectrode assembly including a second electrode adapted to form a sparkgap with said first electrode and a pair of insulators one of whichcarries said second electrode, the other of which is adapted to form abaffle with the first insulator and to receive an ignition cable in atransverse bore formed therein, and a removable extension on said secondelectrode, said extension I having one end thereof projecting into saidcable at a right angle to the axis thereof and intermediate the ends ofsaid transverse bore.

4. A spark plug structure comprising a member arranged for attachment toa cylinder of an' engine and having an electrode therein, a cooperatingelectrode assembly includinga second electrode adapted to form a sparkgap with said first electrode. and a pair of insulators one of whichcarries said second electrode and the other of which is aperturedtransversely to receive an ignition cable for connection to said secondelectrode, a longitudinally extending aperture in said second insulator,and a piercing member extending through said longitudinal aperture toengage said cable laterally, said piercing member being in contact withsaid second-named electrode at its other end.

5. A spark plugstructure comprising a member arranged for attachment toa cylinder of an engine and having an electrode therein, a cooperatingelectrode assembly including a second electrodeadapted to form a sparkgap with said first electrode and a pair of insulators one of whichcarries said second electrode and the other of which is aperturedtransversely to receive an ignition cable for connection to said secondelectrode, a longitudinally extending aperture in said second insulator,and a piercing member extending through said longitudinal aperture toengage said cable laterally.

6. A spark plug structure comprising a member arranged for attachment toa cylinder of an engine and having an electrode therein, a cooper-'ating electrode assembly including a second electrode adapted to form aspark gap with said first electrode and a pair of insulators one ofwhich carries said second electrode and the other of which is adapted topartially fit within the first insulator to form a battle and providedwith a transverse bore to receive an ignition cable for connection tosaid second electrode, means for holding said first insulator inoperative relation with the first mentioned member, and a removableextension on said second electrode, said extension having one endthereof projecting into said cable at a right angle to the axis thereofand intermediate the ends of said transverse bore.

'7. A spark plug structure comprising a member arranged for attachmentto a cylinder of an engine and having an electrode therein, acooperating electrode assembly including a second electrode adapted toform a spark gap with .said first electrode and a pair of complementaryinsulators adapted to partially fit one within the other to form abaille, one of said insulators constituting a support for said secondelectrode and the other being provided with a transversely dis-z posedbore for the reception of an insulated ignition cable for connection tosaid second electrode, a sleeve adapted for engagement with said firstmentioned member and having an inturned annular lip or fiange forengagement with a shoulder on said first insulator forholding the latterfirmly in position, and an electrical shield adapted for frictionalengagement with said sleeve to hold said second insulator in operativerelation with arranged for attachment to a cylinder of an engine andhaving an electrode therein, a cooperating electrode assembly includinga second electrode adapted to form a spark gap with said firstelectrode, and a pair of insulators one of which carries said secondelectrode, the other of which is adapted to form a baffle with the firstinsulator and to receive an ignition cable in a transverse bore thereof,and an extension on said second electrode, said extension having one endthereof projecting into said cable at a right angle to the axis thereofand intermediate the ends of said transverse bore.

9. A spark plug structure comprising a member arranged for attachment toa cylinder of an engine and having an electrode therein, a cooperatingelectrode assembly including a secondelectrode adapted to form a sparkgap with said first electrode and a pair of insulators one of whichcarries said second electrode and the other of which is adapted to forma baffle with the first insulator and to receive an ignition cable forconnection laterally to said second electrode, means for holding saidfirst insulator in operative relation with the first mentioned member,and an electrical shield adapted for frictional engagement with saidlast mentioned means to hold said second insulator in operative relationwith the first insulator, thereby forming a unitary structure which isadapted for quick assembly and disassembly.

10. A spark plug structure comprising a member arranged for attachmentto a cylinder of an engine and having an electrode therein, acooperating electrode assembly including a second electrode one end ofwhich is adapted to form a spark gap with said first electrode and theother end of which is counter-bored, a terminal extension for saidsecond electrode provided with a sharp taper at one end for piercing anignition cable and with a pin at the other end for insertion into saidcounterbore, a pair of insulators one oi which surrounds and supportssaid second electrode, and the other of which is provided with alongitudinal bore for receiving said electrode terminal extension andwith a transverse bore for receiving an ignition cable, a sleevethreaded internaliy for engagement with the first mentioned member andhavin an inturned annular lip or flange adapted to engage a shoulder onthe first insulator for holding the latter firmly in position, and ametallic electrical shield adapted for sliding frictional engagementwith said sleeve to hold said second insulator in operative relationwith the first insulator, thereby forming a unitary structure which maybe quickly assembled and disassembled and providing angular adjustmentor? the structure to receive a cable from any direction in a planeperpendicular to the longitudinal axis of the plug.

ll. An ignition device comprising in combination, a snarl: plugstructure including a member arranged for attachment to an enginecylinder, an electrode assembly fitted within said member and comprisinga centrally disposed electrode having a removable extension, aninsulator havin. a longitudinal bore extending therethrough forreceiving said extension, and a transverse bore intersecting said firstbore and arranged for reception of an insulated ignition cable, and apointed end on said extension adapted to pierce said ignition cablelaterally.

12. A spark plug structure comprising a member mounted for attachment toa cylinder of an engine and having an electrode therewithin, a secondelectrode adapted to cooperate electrically with said first electrode, abody of insulating material surrounding said second electrode, ametallic sleeve held fast to said first named member, means integralwith said sleeve for holding said' insulating body in position withinsaid first named member and a metallic shielding element surrounding theupper portiomcf said insulating body but spaced therefrom, saidshielding element being formed at its lower end for frictionalengagement with said metallic sleeve.

13. A spark plug structure comprising a shell mounted for attachment toa cylinder of an engine and having an electrode therewithin, a secondelectrode adapted to cooperate electrically with said first electrode, abody of insulatfor electrical ing material surrounding said secondelectrode, a metallic shielding element surrounding the upper portion 0!said insulating body, said shielding element being of a diameterconsiderably larger than the diameter of that portion of the insulatingbody which it surrounds, a second body of insulating material interposedbetween said first named insulating body and said shielding element, andmeans for operatlvely connecting said shielding element with said shell,said last named means also serving to maintain said first namedinsulating body in proper position with respect to said shell and secondelectrode.

14. A spark plug structure comprising a member mounted for attachment toa cylinder of an engine and having an electrode therewithin, a secondelectrode adapted to cooperate electrically with said first electrode, abody of insulating material surrounding said second electrode, ametallic shielding element surrounding the upper portion-of saidinsulating body, said shield-- ing element being of .a diameterconsiderably larger than the diameter of that portion 01 the insulatingbody which it surrounds, and a second body of insulating materialinterposed between said first named insulating body and said shieldingelement, and means including a sleeve threadedly engaging said shell,and frictionally engaging said shielding element for holding said firstnamed insulating body against displacement with respect to saidelectrode and shell.

l5. An ignition device comprising in combi-- nation, a spark plugstructure including a member arranged for attachment to a cylinder oi anengine and having an electrode therein; a cooperating electrodesurrounded by an insulator having a recess at one end, said secondelectrode having an extension'one end of which is pointed i'or piercinga cable, a second insulator provided with a projection adapted to fitwithin the recess of said first insulator and 'having a longitudinalbore extending therethrough for receiving said extension'and atransverse bore intersecting said first bore, and an insulated ignitioncable extending into said transverse bore contact with the electrodeextension.

16. A spark plug structure comprising a member arranged for attachmentto a cylinder of an engine and having an electrode therein, a secondelectrode adapted to form a spark gap with said first electrode, and apair of insulators one of which carries said second electrode, the otherof which is adapted to receive an ignition cable in a transverse boreformed therein, said second electrode having one end thereof projectinginto said cable at a right angle to the axis thereof.

17. A spark plug structure comprising a member arranged for attachmentto a cylinder of an engine and having an electrode therein, a secondelectrode adapted to form a spark plug gap with said first electrode, aninsulator which is adapted to receive an ignition cable in a transversebore formed therein, and a removable extension on said second electrodehaving one end thereof projecting into said cable at a right angle tothe axis thereof.

EDWARD B. NOWOSIELSKI.

